Electrocardiographic Findings Among the Total Adult Population of a Large Religious Isolate

Abstract

Electrocardiograms were recorded as part of a survey of 1,303 men and 1,348 women past 15 years of age belonging to a large religious isolate inhabiting regions of northwestern U.S.A. and southwestern Canada. The ECGs were classified according to the Minnesota Code and the abnormalities were related to constitutional characteristics, blood pressure, and serum cholesterol. Major codable ECG items included abnormal Q waves (54 cases), abnormal left axis deviation (44 cases), bundle-branch block (left 10, right 10), T-wave abnormalities (257 cases), prolonged P-R interval (80 cases), and occasional premature beats (143 cases) and showed no significant sex differences. ST-segment depressions were more common among females ( P < 0.005). The males showed a significantly higher frequency of increased R-wave amplitude ( P < 0.005) and more qualitative T-wave changes ( P < 0.005). In general, abnormal ECG features were associated with age, sex, and blood pressure, but not with serum cholesterol, body weight and height, skin-fold thickness, or arm girth. A notable exception was the negative relationship of body weight to high amplitude R waves in young males. In clinical practice, age and sex stratifications will improve the diagnostic power of the ECG.